TYLOSTOMATACEAE 



Plants formed underground, emerging at maturity and consisting of a tough, 

 fibrous, stalk bearing the globular spore sac, the outer wall of which (in Tylostoma) 

 consists of a thickish, sandy layer which either breaks up and falls away soon in flakes 

 or persistently adheres and slowly wears away. The inner layer is a thin, tough, rather 

 firm, persistent membrane which contains the unchambered homogeneous gleba 

 without tramal plates; the spores escaping by a definite apical mouth (at times several) 

 or by an irregular or circumscissile dehiscence. Capillitium present, of varied char- 

 acter, arising from the entire surface of the inner peridium. Basidia club-shaped with 4, 

 irregularly scattered, nearly sessile spores. 



The outer peridium in Queletia has not been described in detail. Lloyd (Myc. 

 Notes, p. 135) say's that it is "apparently a thin white coat that breaks up into granular 

 particles and mostly disappears." Six genera are included in the family by Miss White, 

 five of which are from America. Only two of these, Tylostoma and Queletia, are known 

 east of the Mississippi. Chlamydopus has been found in New Mexico and Washington, 

 Dictyocephalos in Colorado, Battarrea in several western states, and Sphaericeps is 

 known only from Angola in western Africa. See Miss White for descriptions of these. 

 For convenience we include in the key all the genera of the family. With some changes 

 it is copied from Miss White. 



Key to the Genera 



Peridium opening by an apical mouth 



No free volva present; stem not flaring above Tylostoma (p. 149) 



Free volva present; stem flaring above Chlamydopus 



Peridium circumscissile 



Peridium nearly plane below, dehiscing around the basal margin Battarrea 



Peridium spherical, dehiscing at the equator Sphaericeps 



Peridium opening irregularly 



Peridium easily separating from the stem; capillitium not embedded in a tissue . . Queletia (p. 158) 

 Peridium firmly attached to the stem; capillitium embedded in a tissue Dictyocephalos 



TYLOSTOMA Pers. 



Mycelium subterranean, composed of delicate, white, much branched strands 

 which bear here and there white, sclerotium-like balls of various sizes, these developing 

 (apparently slowly) into the full sized buttons. Peridium composed of an outer sandy 

 case formed of delicate flocculence holding the earth,— in which in the button stage is 

 also included the unextended stem,— and an inner, very thin layer formed of delicate, 

 interwoven hyphae which, without apparent change, turn inward and continue as the 

 elements of the gleba. Stalk cylindrical, tough and firm, with a central column of 

 delicate soft, white, cottony tissue; surface usually brown and more or less marked with 

 scales and fibers. Capillitium abundant, arising from the entire inner surface of the 

 peridium. including the base, pale to nearly hyaline, frequently septate, much branched, 

 not rarely with cross bar connections as if anastomosing had occurred (but probably 

 only a method of branching) ; with walls irregular in thickness in the same thread, in 

 places closing the lumen; tapering tips lacking, the ends appearing abrupt as if broken. 



149 



